diff --git a/graphql_parser/src/graphql_parser.ml b/graphql_parser/src/graphql_parser.ml
index 4f38f21..6351d78 100644
--- a/graphql_parser/src/graphql_parser.ml
+++ b/graphql_parser/src/graphql_parser.ml
@@ -188,11 +188,14 @@ let string_value = lift (fun s -> `String s) (quote *> string_chars <* quote)
 let boolean_value = string "true"  *> return (`Bool true) <|>
                     string "false" *> return (`Bool false)
 
-let number_value = lift (fun n ->
+let number_value = number_chars >>= fun n ->
   try
-    `Int (int_of_string n)
+    return (`Int (int_of_string n))
   with Failure _ ->
-    `Float (float_of_string n)) number_chars
+    try
+      return (`Float (float_of_string n))
+    with Failure _ ->
+      fail (Format.sprintf "Invalid number value: %s" n)
 
 let enum_value = name >>= function
   | "true"
diff --git a/graphql_parser/test/data/kitchen_sink.graphql b/graphql_parser/test/data/kitchen_sink.graphql
index 20dbf6d..52e19b5 100644
--- a/graphql_parser/test/data/kitchen_sink.graphql
+++ b/graphql_parser/test/data/kitchen_sink.graphql
@@ -45,6 +45,6 @@ fragment frag on Friend {
 }
 
 {
-  unnamed(truthy: true, falsey: false, nullish: null),
+  unnamed(truthy: true, falsey: false, nullish: null, enum: ECHO),
   query
-}
\ No newline at end of file
+}
diff --git a/graphql_parser/test/data/kitchen_sink.sexp b/graphql_parser/test/data/kitchen_sink.sexp
index 186f75e..a4248f9 100644
--- a/graphql_parser/test/data/kitchen_sink.sexp
+++ b/graphql_parser/test/data/kitchen_sink.sexp
@@ -100,7 +100,8 @@
     ((Field
       ((alias ()) (name unnamed)
        (arguments
-        ((truthy (Bool true)) (falsey (Bool false)) (nullish Null)))
+        ((truthy (Bool true)) (falsey (Bool false)) (nullish Null)
+         (enum (Enum ECHO))))
        (directives ()) (selection_set ())))
      (Field
       ((alias ()) (name query) (arguments ()) (directives ())